This power supply module plugs straight into common bread boards, allowing you to cleanly and easily power your board with a wall wart plug or with wires into screw terminals. It features a variable voltage regulator that can be set to output 3.3 or 5V with a jumper, or any voltage if a potentiometer is added. The input has a rectifier that accepts AC or DC (polarity doesn’t matter)–just make sure the input is about 2V greater than the output you want. Skill level: beginner.